System Design Interview Questions
Practice 968 real System Design interview questions for 2026 — System Design interview questions drawn from actual interviews with detailed solutions to power focused interview preparation. Coverage spans big tech patterns and company-specific flavors from Meta, Amazon, OpenAI, DoorDash, and Google, emphasizing software-engineering fundamentals: high-level architecture, APIs, data models, scaling strategies, and component-level tradeoffs you’ll need to codify on a whiteboard or virtual diagram tool. What’s distinctive in 2026: interviewers evaluate your ability to reason about capacity, latency, consistency, fault tolerance, and operational ownership while making measurable tradeoffs; expect more questions about AI/LLM inference pipelines, vector search and feature stores alongside classic problems like caching, sharding, messaging, and geo-distribution. Prepare by practicing clear HLD-to-LLD transitions, writing concise API contracts, doing back-of-envelope capacity math, and running timed mock interviews that force diagram clarity and follow-up handling. Focus on metrics, failure modes, and deployment/monitoring choices — those separate good answers from great ones.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Design an At-Most-Once Job Scheduler
Design a distributed job scheduler that supports both one-time and recurring jobs. Requirements: - Clients can create jobs with a schedule, payload, r...
Design an Instagram-like platform
Design a large-scale social media platform similar to Instagram. Users should be able to: - create accounts and follow other users - upload photos or ...
Design a basic banking system
System Design: Basic Online Banking with Safe Money Movements Context Design a minimal but production-minded online banking service. It must support c...
Design a crash-resilient file system
Prompt Design a resilient file system that can recover file contents correctly after a system crash (e.g., power loss / kernel panic). The interviewer...
Design a donations service with 3-day rolling totals
Design a service that ingests donations and serves rolling 3-day donation totals. Requirements Core features 1. Ingest donation events: - Each dona...
Extend rules for trip-level aggregates and outputs
Extend Rules Engine: Aggregate Trip-Level Policies Context You previously built an expense policy engine that evaluates per-expense rules (e.g., "a si...
Design a high-scale URL shortener
Design a URL shortening service. Core APIs / Features - Create short URL: accept a long URL and return a short code / short URL. - Redirect: given a s...
Design a KV store with transactions
System Design Prompt Design an in-memory/disk-backed key-value store that supports transactions. Functional requirements - Basic operations: Get(key),...
Design an in-memory database
System Design: In-Memory Key–Value Database for Ultra–Low Latency Context You are designing an in-memory, per-node key–value database optimized for ul...
Design a collaborative spreadsheet backend
Design a web-based spreadsheet service similar to Google Sheets, with emphasis on backend architecture and data models. Focus areas: - Multiple users ...
Design Slack-like multi-tenant global messaging system
Design a team messaging platform similar to Slack that supports multiple organizations (multi-tenancy) and is deployed globally. Functional requiremen...
Optimize MapReduce performance
MapReduce Model and Optimization for Parallel Efficiency and Network Utilization Context You are designing a large-scale batch processing job (e.g., f...
How would you throttle a crawler?
The crawler above is now a production service. Expanding each page requires an outbound HTTP or API call to fetch its links, and upstream services may...
Design a metrics collection and alerting system
Design a metrics collection and alerting system (like a simplified monitoring platform). Functional requirements: - Collect time-series metrics from m...
Design an IAM system for services and users
System Design Prompt Design an Identity and Access Management (IAM) system for an organization/platform. The system must support: - Human users and se...
Design a price drop tracking service
Design a price tracking service like CamelCamelCamel. Requirements: - Users track products and receive alerts when price drops below a threshold. - Pe...
Design a post privacy/visibility system
Design a privacy system for social media posts (similar to Facebook post privacy). Requirements: - Each post can be: Public, Friends, Friends-of-frien...
Design an ad click aggregation service
Design a backend service that ingests ad impression and click events and provides aggregated metrics. Requirements: - Ingest a high-volume stream of e...
Describe how you use Kubernetes
System Design: Practical Kubernetes (K8s) Use and Operations Context: In a technical screen, you are asked to describe how you have used Kubernetes in...
Design a restaurant reservation system
Design an end-to-end restaurant reservation system. The system should allow users to: - Search restaurants by location/time/party size - View availabi...